1. Field of the Invention
The present invention relates to a vacuum cleaner, and more particularly, to a locking device for an exhaust filter of a vacuum cleaner, which can securely lock the exhaust filter installed on an outer surface of the vacuum cleaner.
2. Description of the Prior Art
As shown in FIG. 1, a main body 2 of a vacuum cleaner is formed on both side surfaces thereof with exhaust portions 4 through which air is exhausted. The exhaust portions serve to discharge, to the exterior of the vacuum cleaner, air resulting from removal of foreign substances from air containing the foreign substances introduced into the main body of the vacuum cleaner.
The exhaust portions 4 are formed by attaching both filters 4b and exhaust filter covers 4a to exhaust holes 6a formed on both side surfaces of a casing of the main body of the vacuum cleaner, which includes an upper casing 6 and a lower casing 8, as shown in FIG. 2.
Each exhaust filter cover 4a is fixed to the casing of the main body by fitting a protrusion 4c formed on an outer peripheral surface of the exhaust filter cover into the casing of the main body in which the exhaust holes 6a are formed. Here, each filter 4b serves to finally filter out the foreign substances, which may be contained in the exhausted air. The filter 4b is positioned between the exhaust filter cover 4a and the exhaust hole 6a. 
In general, vibration and noise are generated due to driving of a motor contained within the main body upon operation of the vacuum cleaner. The vibration generated as such is transferred to both the exhaust filter cover 4a and the filter 4b. According to the conventional constitution, since the filter 4b is supported in a state where it is simply inserted between the exhaust filter cover 4a and the main body of the vacuum cleaner without an additional support relationship, the filter 4b is rattled by such vibration. Accordingly, there are probabilities that the filter 4b will come into contact with the cover 4a or the main body of the vacuum cleaner in the vicinity of the filter, and any undesired contact noise will be generated due to such contact.
The present invention is contemplated to solve the above problems in the prior art. An object of the present invention is to provide a locking device for an exhaust filter of a vacuum cleaner, which can perfectly prevent noise generation in the vicinity of the exhaust filter upon operation of the vacuum cleaner by more securely locking the exhaust filter.
According to the present invention for accomplishing the above object, there is provided a locking device for an exhaust filter of a vacuum cleaner, comprising an exhaust filter cover mounted on one side surface of a main body of the vacuum cleaner, and including a plurality of exhaust holes and a plurality of mounting grooves formed on an inner surface of a cylindrical sidewall of the exhaust filter cover; and a filter including a filtering portion for filtering air, and engagement protrusions formed on a cylindrical outer peripheral surface of the filter to be resiliently locked within the mounting grooves, respectively, whereby the filter is resiliently locked within the exhaust filter cover.
According to one embodiment of the present invention, the mounting grooves take a -shape, or bayonet-shape, and the engagement protrusions are inserted into the respective mounting grooves and then rotated in a predetermined direction to be locked within the mounting grooves, respectively.
According to another embodiment of the present invention, engagement protrusions are formed just in front of trail ends of the  -shaped or bayonet-shaped, mounting grooves so as to maintain a state where the engagement protrusions have entered the trail ends of the mounting grooves, respectively.